A Two-Input Polygraph
Archana VenkataramanChristopher Buenrostro
Isaac Rosmarin
Outline
IntroductionDesign Overview
The Physiological SensorsThe Digital Decision-Making Unit (DDMU)The Output Display
Conclusion
Introduction
The polygraph detects stress-related physiological responses commonly linked with deception
Modern-day polygraphs rely on 4 major variables:
The Foundation of a lie-detector examination is in its structureEnvironmental SettingExperience and Conduct of ExaminatorQuestions: Control, Irrelevant, and Relevant
Decisions are based on the assumption that an innocent subject will react more strongly to the control questions and a guilty subject will react more strongly to the relevant questions
Introduction
The project uses 2 inputs to make decision–heart rate and skin conductivity
Heart speeds up during times of emotional stressPerspire during times of emotional stress –increases conductivity
Project divided into three sectionsThe Physiological SensorsThe Digital Decision-Making UnitThe Output Display
Input Devices
Inputs DDMU Video
Data Acquisition Flow Diagram
Heart Rate Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Skin Conductivity
Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Designated Lab Kit
RAM Refresh Block
Input Devices
Inputs DDMU Video
Data Acquisition Flow Diagram
Heart Rate Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Skin Conductivity
Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Designated Lab Kit
RAM Refresh Block
Input Devices
Inputs DDMU Video
Data Acquisition Flow Diagram
Heart Rate Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Skin Conductivity
Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Designated Lab Kit
RAM Refresh Block
Input Devices
Inputs DDMU Video
Data Acquisition Flow Diagram
Heart Rate Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Skin Conductivity
Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Designated Lab Kit
RAM Refresh Block
Input Devices
Inputs DDMU Video
Data Acquisition Flow Diagram
Heart Rate Monitor
Probe PatchesAttached to Test Subject Designated
Lab Kit RAM
Refresh Block
Analog-to-Digital
Converter
Skin Conductivity
Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Input Devices
Inputs DDMU Video
Data Acquisition Flow Diagram
Heart Rate Monitor
Probe PatchesAttached to Test Subject Designated
Lab Kit RAM
Refresh Block
Analog-to-Digital
Converter
Skin Conductivity
Monitor
Probe PatchesAttached to Test Subject
Analog-to-Digital
Converter
Electrocardiogram Heart Monitor
*Images from http://ramseyelectronics.com
Inputs DDMU Video
Ramsey Electronics ECG1C
Skin Conductivity Monitor
*Images from http://vismod.media.mit.edu/tech-reports/TR-542.pdfwith credit to Rosalind W. Picard and Jocelyn Scheirer
Inputs DDMU Video
The Galvactivator
The Digital Decision-Making Unit
Design OverviewUser InterfaceDecision-Making Portion Based on Polygraph DataAdditional Functions
Obtain Data Stored Externally in RAMPrepare/Send Data to Display Unit
Data to Be Displayed on
Screen
MemoryModule
DisplayDriver
Decision-Making
Algorithm
User Commands
CaptureUser Inputs
Data Register
Screen Capture Commands
To Memory Interface Module
To Memory Interface Module
Inputs DDMU Video
Capturing User Commands
Module registers all user inputs and passes them to appropriate moduleUser Commands:
Type of QuestionAnalyze ResultsDisplay DataStore DataScreen Capture
Data to Be Displayed on
Screen
MemoryModule
DisplayDriver
Decision-Making
Algorithm
User Commands
CaptureUser Inputs
Data Register
To Memory Interface Module
Screen Capture Commands
To Memory Interface Module
Inputs DDMU Video
Decision-Making Algorithms
Main Module of the DDMU –Analyzes sensor data and outputs binary “TRUTH/LIE”decisionDigital Pre-Processing on data to remove extraneous, environmental factors
Average incoming dataHighpass Filter
Implement one or more of following algorithms:
Compare statistics of time signalConvert to frequency domain and compareHypothesis Testing
Data to Be Displayed on
Screen
MemoryModule
DisplayDriver
Decision-Making
Algorithm
User Commands
CaptureUser Inputs
Data Register
To Memory Interface Module
Screen Capture Commands
To Memory Interface Module
Inputs DDMU Video
The Memory Module and Data Register
The Memory Module signals Memory Interface to Read from and Write to RAM by asserting a “request” signalData Register holds critical values for the Decision-Making Algorithm:
Time sequences to be comparedComputed Statistics
Data to Be Displayed on
Screen
MemoryModule
DisplayDriver
Decision-Making
Algorithm
User Commands
CaptureUser Inputs
Data Register
To Memory Interface Module
Screen Capture Commands
To Memory Interface Module
Inputs DDMU Video
Display Driver
Gathers data to be sent to Display Unit
Sensor DataDecision (T/F)Screen Capture Command
Data to Be Displayed on
Screen
MemoryModule
DisplayDriver
Decision-Making
Algorithm
User Commands
CaptureUser Inputs
Data Register
To Memory Interface Module
Screen Capture Commands
To Memory Interface Module
Inputs DDMU Video
Video Display
Job of the Video DisplayTake in data and convert to a visually appealing formatDisplay dataSave previous data for reference
Inputs DDMU Video
On computer monitorLike PS3/Lab 4Higher Resolution
Inputs DDMU Video
Video Output
Register data on vsync refreshConvert data into an eye-pleasing format
Inputs DDMU Video
Data Inputs
Compresses data to saveDisplays previous dataInteracts with onboard RAMChanges based on user input
Inputs DDMU Video
Video Storage
Conclusion
Design is modular Project is good extension to material presented in classPolygraph is an interesting real-world application